The campaign was started in the wake of a series of high-profile detentions of photographers by police under section 44 of the Terrorism Act 2000. Last week, the European Court of Human Rights ruled that the stop and search powers detailed in this act breached the right to privacy. As I argued at the time, anti-terror legislation and its impact on civil liberties is issue that affects all of us, not just photographers.

You can follow events in Trafalgar Square on this blog tomorrow or via twitter, where I will be posting regular updates, pictures and audio clips.